[PATCH v3 0/4] iio: adc: ad9467: Support alternative backends

[Tomas Melin]

To facilitate backends with different set of features, add support
for defining capabilites provided by the backend. These capabilites
typically extend beyond a single operation and are therefore not
directly linked to if a single function call is implemented or not.
Furthermore, the capabilites determine if a certain set of operations
should be attempted, or skipped by the frontend. This way
the frontend driver can work with a minimalistic set of features and
still have the device in fully functional state.

Signed-off-by: Tomas Melin <tomas.melin@xxxxxxxxxxx>
---
Changes in v3:
- Reduce set of capabilities to only include calibration. The other
  ones propsed in V2 can be seen as subset of calibration, or single
  operation failing with opnotsupported
- Rename backends checking function
- Relocate caps field inside backend struct (pahole)
- Add kernel-docs
- Add capabilites for exisiting backend variants
- Link to v2: https://lore.kernel.org/r/20260113-b4-ad9467-optional-backend-v2-0-0a27e7e72f41@xxxxxxxxxxx

Changes in v2:
- Added industrialio-backend capabilities feature
- Removed acceptance for fully optional backend, instead require atleast
  minimalistic backend to exist
- Switched to FIELD_MODIFY()
- Fixed kernel test robot reported failure for missing bitfield.h
- Link to v1: https://lore.kernel.org/r/20251216-b4-ad9467-optional-backend-v1-0-83e61531ef4d@xxxxxxxxxxx

---
Tomas Melin (4):
      iio: adc: ad9467: include two's complement in default mode
      iio: industrialio-backend: support backend capabilities
      iio: adc: adi-axi-adc: define supported iio-backend capabilities
      iio: adc: ad9467: check for backend capabilities

 drivers/iio/adc/ad9467.c           | 44 ++++++++++++++++++++++++++++++--------
 drivers/iio/adc/adi-axi-adc.c      |  2 ++
 drivers/iio/industrialio-backend.c | 17 +++++++++++++++
 include/linux/iio/backend.h        | 17 +++++++++++++++
 4 files changed, 71 insertions(+), 9 deletions(-)
---
base-commit: a7b10f0963c651a6406d958a5f64b9c5594f84da
change-id: 20251215-b4-ad9467-optional-backend-23f1099ee4d7

Best regards,
-- 
Tomas Melin <tomas.melin@xxxxxxxxxxx>